Efavirenz
| Evidence Level: L5 | Predicted Indications: 3 |
Table of Contents
Efavirenz: From HIV-1 Infection to Feline Acquired Immunodeficiency Syndrome
One-Sentence Summary
Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) marketed for HIV-1 infection in humans. The TxGNN model predicts it may be effective for feline acquired immunodeficiency syndrome (FIV infection in cats). Support is weak: 1 in vitro biochemical/structural study and 2 human HIV-1 trials that do not address cats, with no feline efficacy data.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | HIV-1 infection (the approved-indication text is blank in the US licence records; this is based on the drug’s known class and use) |
| Predicted New Indication | Feline acquired immunodeficiency syndrome |
| TxGNN Prediction Score | 99.80% |
| Evidence Level | L4 (preclinical/mechanism studies only) |
| US Market Status | ✓ Marketed |
| Number of NDAs | 18 (the listed licences are all generic ANDAs) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the source record. Efavirenz belongs to the NNRTI class, which blocks HIV-1 reverse transcriptase (RT). Its efficacy in HIV-1 infection is established.
Feline immunodeficiency virus (FIV) is a lentivirus related to HIV. It causes an AIDS-like syndrome in cats, and no effective treatment has been established for infected cats. Inhibiting reverse transcriptase is therefore biologically plausible. A 2023 study compared NNRTIs (nevirapine, efavirenz, rilpivirine) against feline and human immunodeficiency virus enzymes to assess this potential.
Two cautions apply:
- NNRTI binding pockets differ between lentiviral RTs, so activity against HIV-1 RT does not guarantee activity against FIV RT.
- The very high TxGNN score most likely reflects efavirenz’s dense anti-HIV links in the knowledge graph, not FIV-specific evidence.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT01263015 | Phase 3 | Completed | 844 | Dolutegravir + abacavir/lamivudine vs. efavirenz/emtricitabine/tenofovir (Atripla) in treatment-naive HIV-1 adults. Efavirenz was the comparator; no FIV data |
| NCT00951015 | Phase 2 | Completed | 208 | Once-daily dose selection of dolutegravir in treatment-naive HIV-1 adults, with efavirenz apparently as the comparator arm; no FIV data |
Both trials were run in HIV-1-infected humans, so they provide no direct evidence for FIV. Their Phase 2/3 labels do not raise the evidence level.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 38031646 | 2023 | Preclinical (in vitro biochemical/structural) | Journal of Veterinary Science | Compared nevirapine, efavirenz and rilpivirine against feline and human immunodeficiency virus enzymes to explore NNRTIs for FIV. The available abstract is truncated, so the actual results cannot be confirmed |
US Market Information
| Authorization Number | Product Name | Dosage Form | Manufacturer |
|---|---|---|---|
| ANDA204766 | Efavirenz | Film-coated tablet | Cipla USA Inc. |
| ANDA078064 | Efavirenz | Capsule | Aurobindo Pharma Limited |
| ANDA077673 | Efavirenz | Film-coated tablet | Aurobindo Pharma Limited |
| ANDA078886 | Efavirenz | Film-coated tablet | Camber Pharmaceuticals, Inc. |
Approved-indication text is blank in the source records. These are human oral products, and no veterinary product is listed. ANDA078064 appears twice in the source and is shown once.
Safety Considerations
Please refer to the package insert for safety information.
Conclusion and Next Steps
Decision: Hold
Rationale: The only relevant evidence is one in vitro biochemical/structural study, and no feline in vivo efficacy or safety data exist. The two listed trials are human HIV-1 studies in which efavirenz was only a comparator. The high TxGNN score alone is not enough to justify moving forward.
To proceed, the following is needed:
- Full text of PMID 38031646 to confirm efavirenz’s actual activity against FIV reverse transcriptase versus HIV-1 reverse transcriptase
- Cell-based FIV antiviral activity data (EC50, selectivity)
- Feline pharmacokinetic and safety data, including tolerability, since the source lacks warning and contraindication information
- The FDA package insert and MOA data to close the current data gaps
- Veterinary regulatory and use-context assessment, since all listed products are for humans
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.